EVIDENCE FOR DOMAIN-WALL TUNNELING IN A QUASI-ONE-DIMENSIONAL FERROMAGNET

We have studied the motion of magnetic domain walls in very small diam eter ferromagnetic wires. Our results suggest that walls do not move s moothly along the wire, but can be trapped at pinning sites. It appear s that they escape from these sites by thermal activation at high temp eratures, and quantum tunnelling at low temperatures. Tunnelling domin ates below similar to 5 K, which is about an order of magnitude higher than predicted by the current theory.